The invention relates to a hydraulic steering device, having a housing in which an inner control slider and an outer control slider are arranged so that they are rotatable relative to one another and which together are arranged as alterable flow path means between a supply connection arrangement and a working connection arrangement.
Such a steering device is known, for example, from DE 43 42 933 A1.
In steering devices of that kind, the supply connection arrangement generally comprises a pump connection and a tank connection. The working connection arrangement generally comprises two working connections. Depending on which of the two working connections is acted upon by pressure, a connected steering motor is moved in one or the other direction.
In most cases the inner control slider is moved by means of a steering handwheel, that is, is rotated with respect to the outer control slider. In this case a flow path between the pump connection and the corresponding working connection, and between the other working connection and the tank connection is unblocked with more or less throttling. Hydraulic fluid therefore flows from the pump by way of the steering motor to the tank again. At the same time, the hydraulic fluid actuates a measuring motor which rotates the outer control slider relative to the inner control slider and thus brings both control sliders into their original aligned position again in which the flow path is closed.
In some cases it is desirable to be able to steer a vehicle that is equipped with such a steering device not only from a driver position using the steering handwheel, but also, for example, in the case of self-propelled working machines, from several positions.
This has primarily been achieved until now by mounting a drive motor on the steering handwheel shaft, which motor, when suitably actuated, takes on the function of the human hand as drive means for that hand wheel shaft. Additional installation space is required for that motor, however.